The present invention relates generally to agricultural implements of the type having foldable tool bars including a central horizontal main section and a pair of outboard wing sections connected to a respective end portion of the tool bar. The wing sections are moveable between a substantially horizontally extended operative earth-working position where they may follow rolling ground conditions and a transport position which appreciably reduces the overall width of the implement.
In the farm industry, the trend toward more powerful tractors and the desirability to increase productivity and work larger areas of ground has resulted in increasing of the weight and working widths of implements. For example, some planters, discs, cultivators, fertilizers and other farm implements when mounted on a tool bar have a working path width in excess of forty feet. The use of foldable tool bar wings has facilitated passage of the implements through gates and over roads as well as storage of the implement. To increase the maneuverability of this size of implement for off field or road transit conditions, it is known to have some form of articulation of the tool bar support to decrease the width of the implement.
In this regard, a collapsible farm implement has a tool bar with a central horizontal main section attached to a wheeled frame or cart such as a wheeled trailer arrangement, and a pair of outboard tool bar wing sections connected to the central main tool bar section to move between a working position and a transport position. Farm tools such as planters, discs, cultivators, fertilizers and other such farm tools are mounted to the tool bar and spaced therealong so that a number of rows will be worked by the farm tools. The working or operational field use position of the tool bar positions the tool bar wing sections generally parallel to one another and extended in a direction generally crosswise to the direction of the farm implement travel. The width between the outer tips of the respective tool bar wing sections could thus exceed forty feet in the working position.
The transport position is provided by moving the tool bar wings to reduce the effective width of the implement. In the retracted, transport position, the implement has a much narrower width, comparable to the width of the tractor. When in the transport position, the collapsed implement has greatly increased maneuverability for travel down narrower roads, through gates, around turns, etc.
It is also desirable that when the tool bar is in the transport position, the working farm tools mounted on the tool bar are raised so that they do not contact the ground when in transit. Contact with the ground when in transit can damage the farm tools.
On the other hand, when the tool bar is in the working position, it is desirable to maintain the working farm tools in contact with the ground so that they effectively work the ground. It is desirable for a tool bar to have the capability of flexing in the field so that the tools may follow the contour of the ground and also the capability of being collapsed for transport. To maintain the farm tools in a working position, it is desirable to provide a downward force on the tool bar wings which is adjustable to accommodate varying field conditions such as the type of soil being worked.
Numerous mechanisms are known which allow a wing to be lifted, lowered and rigidly secured or locked to the main section when in the working position. These mechanisms allow the operator to lift the wing relative to the implement when transporting or storing the implement Some of such mechanisms are shown in U.S. Pat. Nos. 4,030,551; 4,046,203; 4,061,195; and 4,700,784. Other mechanisms provide for folding the wings behind the main section of the implements as seen in U.S. Pat. No. 4,496,004. Other mechanisms provide for exerting a downward force on the tool bar as disclosed in U.S. Pat. 4,915,014.
A need has long been recognized in the farm industry for a reliable and simple mechanism for a collapsible implement which is durable and allows the wings to be secured in both the working and transport position. It is also desirable to provide a retractable tool bar that may be operated by one person.